The present invention relates generally to marine structures. More particularly, the present invention concerns a wall suitable for use in the construction of wharves, docks, piers, and the like.
In the past, marine structures have been fabricated using various methods. One such method involves driving pilings into the sea bed adjacent to the shore. Typically the pilings are driven in a straight line which defines the eventual contour of the wharf, pier or similar structure to be built. When all the pilings have been driven to a suitable depth and adequately braced, a channel is dredged adjacent to the pilings to accommodate seagoing vessels.
Pilings are not well-suited for use in rocky areas or in areas where the bottom material is especially soft. In the former case it is difficult to drive pilings through rock; as to the latter case, it is difficult to maintain channels adjacent to the wharf without continually dredging them clear.
Another type of marine wall construction involves the use of caissons. The caissons are first fabricated and then floated into position where the marine wall is to built. When in position, the caissons are sunk by use of appropriate kinds of ballast. The sinking operation, however, is tricky because the caissons must be sunk so as to be in proper alignment with the previously positioned and submerged caissons. The space between the caissons and the shore, for example, is then filled with rocks or other material in order to bring the coastal area up to the marine wall.
The caisson construction method is, however, difficult, costly and time consuming.
Another form of marine wall construction involves the use of sheet pilings. The sheet pilings are individually driven adjacent to one another in order to define the front wall of the marine structure. When all the pilings have been driven, the area between the piling and the shore line is then filled with suitable material so as to bring a level surface to the edge of the pilings. In addition, some steps are ordinarily taken to tie back the upper ends of the pilings in a conventional fashion to prevent earth pressure from forcing the pilings outwardly away from the shore. Like the conventional piling method, the sheet piling method is also not well suited to all bottom conditions. Moreover, the sheet piling method is extremely expensive to use since a continuous wall of individually driven pilings is required. Moreover, with the cost of materials in today's economy, steel is not particularly economical to use.
Concrete walls, cast in place, have also been used for marine structures. This method of construction is, however, very expensive and time consuming. For example, a coffer dam is usually required before the construction can commence. And, the foundation must often be dug to bedrock.
One other method of erecting marine walls involves the use of hexagonal panels provided with rearwardly extending truss like members. The facing panels were submerged and placed on a previously submerged footer. The region behind the facing panels is thereafter filled with crushed rock or gravel which interacts with the trusses to maintain the wall in it configuration. Such a wall is disclosed in U.S. Pat. No. 4,045,965 which issued to Henri Vidal on Sept. 6, 1977.
As can be seen from the patent, that earlier construction required the handling and positioning not only of wall panels, but also of the truss members which were then attached to the rear panels. Moreover, a separate vertical truss system was employed to position the horizontal trusses during the backfill procedure. Accordingly, even this more recent system is capable of significant and further improvement.